| Summary: | Understanding the effects of disturbances on the physical-chemical quality of ecosystems
is a crucial step to the development of ecosystem assessment tools. 95 sampling sites
distributed among 4 categories of disturbance, i.e.: reference, logging,
formerly and currently gold mining, were characterized using stream physical and chemical
variables. Our hypotheses were: (i) logging and gold mining activities primarily affect
the physical habitat structure of streams and (ii) both have an effect on chemical
environments through nutrient and/or fine particulate resuspension. We demonstrate that
physical variables describing the river bottom, and suspended solids discriminate both
current and formerly gold mined sites from reference sites, while, whatever the type of
impact encountered, nutrient concentrations do not prove relevant to measure human
impacts. To understand distribution patterns of aquatic organism across FG, future
research should thus aim at examining the match between physical-chemical and biological
classifications of small streams under reference and impacted conditions.
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